Device in an evaporative cooler

ABSTRACT

In an evaporative cooler having a casing, a multilayer type contact body and means for supplying water to selected channels in the contact body, the top edges of the contact body are formed to define outwardly widened openings communicating with only selected channels in the body. The water supply means supplies water to only some of the openings so that alternating channels on the contact body are passed with both water and air and the remainder only with air. As a result the formation of mist at the discharge end of the cooler can be avoided.

This is a continuation of application Serial No. 944,248 filed Sept. 21,1978, now abandoned.

The present invention relates to a device in an evaporative cooler, suchas a cooling tower, which comprises at least one contact body of themulti-layer type housed in a casing and having gaps existing between thelayers through which air and water are passed in countercurrentrelation.

With coolers of the kind stated by way of introduction there exists theproblem, especially at low air temperatures, that the moist air producedin the cooling tower when escaping into the atmosphere forms mist cloudsby condensation of steam. To counteract this formation of mist annoyingthe surroundings it is known to intermix the moist air leaving thecooler with another preheated air stream. According to U.S. Pat. No.3,997,635, this other heated air stream is obtained by excluding some ofthe channels or passages of the cooler from the supply of water, wherebythe air in those channels will be heated by the heat-conductive contactwith the coat of water in adjacent channels. In the discharge from thecontact body the heated air is intermixed with the moist air at such aproportion that the mixture of air when re-entering the atmosphere willnot form any mist.

It has been proved that by use of the method and device according toU.S. Pat. No. 3,997,635 can effectively prevent mist formation byevaporative coolers. However, there still exists the problem of how, ina simple and effective manner, to provide devices for subdividing thecontact body into channels or gaps to which water is supplied, andchannels or gaps which are kept dry, i.e., which are excluded from thewater supply.

Thus, one main object of the present invention is to provide a simpleand effective device in evaporative coolers for subdividing the contactbody into dry and wet channels.

Another object of the invention is to provide a simple water supply tothe wet channels of the compact body.

A further object of the invention is to provide a device by whichoverflow of water from the wet to the dry channels is prevented.

A still further object of the present invention is to provide meanspreventing splashing from the wet channels to be propagated into the dryheated air. In this connection, there may be mentioned that aconventional drop eliminator cannot be operated in the air mixture, butshould much impair the result, since it should act as a moistener to theair leaving the dry channels.

These and other objects are attained by the device according to theinvention having received the characteristics stated in the appendedclaims.

Further objects, characteristics and advantages of the invention willbecome apparent from the following description in connection with thedrawings which show preferred embodiments of the invention.

FIG. 1 shows a vertical section through an evaporative cooler, such as acooling tower of the cross-current type, to which the invention has beenapplied.

FIG. 2 shows a similar section as presented in FIG. 1 through a coolingtower of the counter-current type.

FIG. 3 is a perspective view of the top part of a contact body for thecooler of FIG. 1.

FIG. 4 is a perspective view of the top part of a contact body for thecooler of FIG. 2.

FIG. 5 is a side view of vertical jointing of two contact bodies, and

FIG. 5a shows a section following the line A--A in FIG. 5.

FIG. 6 is a top view of a portion of lateral jointing of two contactbodies, the left-hand part of FIG. 6 corresponding to the view B--B inFIG. 5. FIG. 7 shows a view similar to FIG. 6 of the contact bodies whenbrought together.

The cooling tower shown in FIG. 1 comprises a casing 12 which housesseveral contact bodies 10 each of which is composed of layers or sheets52, 54 (see also FIG. 3) which are disposed in parallel so as to formbetween them vertical gaps or channels. In the shown embodiment thelayers are all corrugated with the corrugations crossing one another inevery second layer, as is indicated with dashed lines in the upper partof the contact body 10. All corrugations extend with an angle to thevertical line and bear against one another at the pointwise distributedplaces of contact. This structure is known from e.g. the U.S. Pat. Nos.3,682,747 and 3,415,502. The layers may be of plastic or other materialwhich is scarcely permeable to water.

The casing 12 is at opposite sides formed with lateral openings 14 foratmospheric air which enters in the direction of the arrow 16. Thecasing 12 has at its top a discharge opening 18 within which is providedan impeller 20 which is driven by a motor 22. The atmospheric air suckedin through the lateral openings 14 will thus be caused by the impeller20 to flow in a mainly vertical direction upwards after the passagethrough the contact bodies 10 as indicated by the arrows 24. Positionedabove the contact bodies 10 are water distributing systems whichcomprise a main 26 and branch pipes 28 and 30, which are equipped withvalves 32, 34 for control or stopping of the water supply. The branchpipe 30 opens into a trough 36 positioned above the contact body 10 andhaving a perforated bottom for downward flow of the water into thecontact body. The other branch pipe 28 is divided into further branches,of which two, denoted 38, 40, are shown in the drawing. These two branchpipes open into distributor pipes 42, 44 mounted horizontally in the topface of the contact body as will be explained in connection with thedescription of FIG. 3.

The cooled water which has passed through the contact bodies 10, iscollected in a sump 46 at the bottom of the cooling tower and isdischarged through a pipe 48 controlled by a valve 50 to the place ofutilization. Upon renewed heating at the place of utilization the wateris returned through the main 26 to the cooling tower to be supplied tothe contact bodies 10, the water then flowing in downward directionthrough the gaps and there meeting the upwards advancing air, the waterthereby being cooled and the air taking up moisture until saturation.

In normal operation during the warmer season, when the demand on coolingcapacity is greatest, full utilization of the evaporative capacity ofthe cooling tower is rendered possible so that all water is suppliedfrom the main 26 via the branch pipes 30 to the trough 36 from which itis distributed over the entire top face of the contact body. If,however, the temperature of the cooling water when entering the tower isso high in relation to that of the atmospheric air, for example at arelatively low air temperature, that the escaping saturated air whenreturning into the atmosphere should precipitate steam in the form ofclouds of mist, the water is supplied through the branch pipes 28 and38, 40 to the distribution pipes 42, 44 from where it is fed into, e.g.,every second gap between the layers of the contact body 10. According tothe present invention, this is accomplished by a specific design of thetop side of the contact body which is shown in FIG. 3.

The contact body in FIG. 3 consists, as described above, of corrugatedlayers 52, 54 which are disposed in parallel so that between themvertical gaps or channels are formed. The layers which are manufacturedby vacuum forming or pressing, for example, are formed, according to theinvention with widened portion 52a or 54a, respectively, which portionsare recurrent with even spacing and interconnected by an intermediateportion 53. When the layers are assembled to form the contact body,these widened portions 52a, 54a, 53 will together form a box-shaped,funnel-like mouth which is open downwards towards the gaps or thechannels existing between the layers. The widened portions 52a, 54aprojecting in opposite directions from the centre line of each of thelayers concerned will thus constitute alternately the long side walls ofbox-shaped funnel openings to adjacent gaps in the contact body. In thisway the contact body 10 will be subdivided at its top into severalgroups of openings, in the shown embodiment two groups, which optionallycan be supplied with water or be kept dry. By placing the distributionpipes 42, 44 into recesses 43 in the lateral walls of the funnels andproviding discharge openings (which are not visible in the figurebecause they are positioned at the underside of the pipes) at optionalfunnel-shaped mouths, water can optionally be supplied to predeterminedgaps in the contact body. In the embodiment shown in FIG. 3, forexample, water is supplied to each box-shaped funnel adjacent each otherin the transverse direction of the contact body, which implies thatwater will be poured into each second gap in the contact body, whilegaps positioned therebetween will be kept dry. For distribution of thewater in the longitudinal direction of the body a plurality of pipes 42,44 are arranged, their number in the shown example being two. When nowair enters the contact body at places indicated by the arrow 16 (seealso FIG. 1) the air leaving the contact body 10 will be constituted byalternately dry, preheated air currents and moistened air currents, ashas been described above. In order to cause the water to be sprayed morequickly in the contact body 10, at least the upper portion of the bodymay have corrugations with a minor angle to the horizontal plane, as isdisclosed in the co-pending U.S. Patent Application Ser. No. 944,246filed Sept. 21, 1978 concurrently herewith.

In the embodiment of cooling towers shown in FIG. 1 several contactbodies 10 are mounted one on top of the other, their number in the showncase being two bodies. In order to ensure maintenance of the subdivisioninto dry or wet channels through the entire cooling tower fill, theupper contact body 10 and the lower contact body 10a in FIG. 1 have aspecific shape at the surfaces facing one another, which shape is shownin FIGS. 5 and 5a. The layers in the upper contact body will in themanufacturing process at the bottom side also be formed with widenedportions in a manner similar to that at the top side, the widenedportions at the bottom side being devised when the layers are joinedtogether to form the contact body to define a socket 56 which hasconnection with those gaps or channels which on the top side of thecontact body are supplied with water through the distribution pipes 42,44. The layers of the lower contact body 10a are in the manufacturingprocess also formed with widened portions in the manner which has beendescribed above, which widening portions in the assembling operationform a socket 58 which, however, has greater length and width than thesocket 56. When assembling the contact bodies 10 and 10a to form acooling tower fill, the arrangement is such that the sockets 56 protrudedown into the sockets 58, which also have connection with every secondchannel or gap in the lower contact body 10a. In this way, there isensured a transfer of water from the upper contact body 10 to the lowerbody 10a in every second passageway only without any water being capableof migrating over into the dry channels or gaps.

In order to join together the contact bodies 10 in lateral directionwhile maintaining the subdivision into wet and dry channels, the lateralfaces of the contact bodies also have a specific shape which is shown inFIGS. 6 and 7. The left-hand part of FIG. 6 corresponds here to thelateral edge 60 of the contact body 10 in FIG. 5 viewed along the lineB--B, whereas the right-hand part of FIG. 6 constitutes the reversedlateral edge 62 of an adjacent package.

As is evident from the FIGS. 6 and 7, every second layer of the contactbody 10 is longer and every second one shorter in the fill so that azigzag-shaped edge face is formed. When the packages are put together,as shown in FIG. 7, the tongues 64 thus formed in every second layer 10will project into the gap 66 formed between the tongues of the opposedpackage. The edges 68 of the layers 10 are shaped, e.g. planed, to makegood contact with one another. By the arrangement with tongues 64 andgaps 66 a guiding for the plane edge portions of the layers 10 isobtained so as to make sure that they will bear against each other.

The main object with this jointing is to keep the moist and the dry airseparated from each other at the transition from one package or body 10to the next following package or body 10. This is rendered possible bythe fact that the pressure drop always is the same in the dry as well asin the wet channels, for which reason no tendency exists in the air topass from one gap or channel into another. Therefore, the shown jointingwith abutment of the edges 68 is sufficient to maintain the subdivisionbetween dry and wet channels at a transition from one package 10 to thenext one. To prevent water or water drops from becoming entrained by theair and passing over from the wet to the dry channels, the body isshaped so that the corrugations and the gaps formed by them at the edgesides of the body 10 run obliquely upwards so as to form dropseparators, or so-called eliminators 11 (FIGS. 1 and 5), which trap thewater to cause it to flow back towards the interior of the contact body.This is particularly important not only at the air discharge side, butalso at the intake side since water may force its way to the edge andpenetrate into the dry channels, for which reason the corrugationsthere, too, ought to have this upward inclination. The gaps then directthe air downwards at the intake side and upwards at the discharge sideso that the air forces the water back into the interior of the body 10or prevents the discharged air from entraining water from the interiorof the contact body.

In order to reinforce the sealing effect between the edge portions, eachof the opposed edge portions may have, as is shown in FIGS. 6 and 7 forthe upper layers, over its entire length a sealing flange 70 which isbent out in opposite directions so that a broader sealing surface isformed along the entire length of the edge. This is especially suitablewhen the sheets of material forming the layers of the contact body 10are thin.

In the embodiment shown in FIG. 2, the invention is illustrated appliedto a cooling tower of the counter-current type which comprises a casing72 housing contact bodies 74 built up in the same manner as the contactbodies 10, which manner has been described in connection with FIG. 1.Through openings 76 in the casing, atmospheric air is sucked in by animpeller member 78 with driving motor 80 located in an opening 82. Thesucked-in air which is marked by the arrows 84, is blown out after thepassage through the bodies 74 into the opening 82 as is indicated by thearrow 36. Positioned above the contact bodies are water distributingsystems comprising a main 88 and two branch pipes the water supply towhich is controlled by valves 94, 96. The branch pipe 90 is positionedabove the packages 74 and equipped with sprayers 98 which distribute thewater over the entire top face of the packages or contact bodies 74 whenwater is supplied to the pipe 90. The other branch pipe 92 is inconnection with branch pipes 100 which open into distribution pipes 102mounted horizontally in the top faces of the contact bodies 74 anddescribed in more detail with reference to FIG. 4. The cooled waterwhich has passed through the bodies 74 is collected in a sump 104 at thebottom of the tower and is discharged through a pipe 106 controlled by avalve 108 to the place of utilization. In the embodiment shown in FIG. 2the cooling tower has two fills or bodies 74 located side by side. Thebodies 74 are at their facing sides attached to a sealing wall 110 whichprevents water from penetrating around the corners of the layers intothe dry channels. This kind of sealing is rendered possible by the factthat air and water in counter-current mainly flow vertically through thepackages and not laterally (unless where caused by the inclination ofthe channels). Thus, any jointing in lateral direction is not requiredand normally neither in vertical direction, since the overall height ofcounter-current towers normally is 1500 mms at the utmost. However, ifdesired, a vertical jointing can be made in the manner shown in FIGS. 5and 5a.

The contact body 74 presented in more detail in FIG. 4, consists ofcorrugated layers 112, 114. These have at the edge a plane, verticallyupwards projecting edge part or rim which is positioned centrally overcorrugations of the layer, which edge part in the manufacturing processis formed with laterally widened portions 116 connected with the centraledge portion or rim via intermediate portions 118. When the layers areassembled with the widened portions 116 facing one another, said widenedportions 116 will form a box-shaped, funnel-like mouth or outlet to thegaps or channels in every second layer. The distribution pipes 102 arelocated in recesses 120 in the lateral walls of the funnel-shaped boxesand are formed with downwards directed holes or openings (not visible)through which water can be supplied to the box and from there to theassociated channel or gaps. As long as water is supplied to the branchpipes 92, 100 and 102 only, water will be poured into every secondchannel of the contact body 74, whereas water will be poured into allchannels of the contact body when water is supplied to the pipe 90 andthe sprayers 98.

The shown water supply affords, in addition to the possibility ofeffectively subdividing the contact bodies into wet and dry channels,further advantages such as a lower overall height due to the embeddingof the water distribution pipes in the contact body, whilesimultaneously solving the splash problems mentioned by way ofintroduction hereto.

As is evident from the above, a device has been provided for subdividingthe contact body into wet and dry channels in a simple and effectiveway. It is obvious in this connection that the shown embodiments areexamples only of ways of realizing the invention and that they can bevaried in many respects without departing from the basic inventive idea.Thus, it is not always necessary to retain the subdivision into wet anddry channels through the entire body, instead this subdivision may,where suitable, be limited to that part of the tower where the airleaves the same. In this connection, the jointing shown in FIGS. 5 and5a between the fill packages or contact bodies may be eliminated, forexample. In case of cross-current flow a mist-free part can be built inat the discharge side of the body 10, where the air leaves the same.Similarly, the water supply or the fills may be formed so that everythird or every fourth channel is kept dry or any other combination bemade depending on the heat load, danger of formation of mist etc.Instead of pipes for the water supply every other suitable supply means,such as troughs having various shape such as having different sectionsfor different parts of the contact body may, of course, be applied.

I claim:
 1. A contact body of the multilayer type comprising at leastone pair of contact body units, located one on top of another within acasing, said contact body units each comprising a plurality of adjacentlayers having upper and lower edges at least one of which abuts anadjacent body above or below it in their longitudinal direction, saidlayers in said contact body units being alternately bent along saidedges, transversely to said longitudinal direction, with adjacent bentedge portions of adjacent layers being interconnected, whereby thelayers cooperate to define at least two groups of openings in thecontact body which communicate only with corresponding openings in anadjacent contact body above or below it, at least one group of openingshaving the shape of sockets with one socket being telescopicallyinserted only into another single corresponding opening in an adjacentcontact body.
 2. In an evaporative cooler including, a casing, at leastone contact body of the multi-layer type located in said casing andformed with channels existing between the layers and which all arepassed by air, and means for supplying water to selected channels insaid body from above the body, the improvement comprising said contactbody comprising layers having top longitudinally extending edges formedwith recurrent laterally outward widened portions that correspond to thelaterally outward widened portions of adjacent layers for formingelongated water supply openings at the top of the contact body wherebythe contact body is subdivided at its top into at least two groups ofelongated openings of which at least one of the groups communicates withpart of the channels only, such group being disposed in relation to saidwater supply means to be supplied with water and define water carryingchannels while the other group of openings define water-free openingsleading to water-free channels; said layers having corrugations formedtherein inclined to the vertical, with the corrugations in each layercrossing the corrugations on adjacent layers thereby to distribute thewater supply in a lateral direction to those portions of the watercarrying channels that are located below the water-free group ofopenings; said contact body being formed of at least two adjacentcontact body units having facing side edges, with the layers of eachunits, at said facing edges being alternately displaced relatively toone another whereby certain edges project from the unit to form tonguesdefining gaps therebetween, which tongues are received in the gapsdefined between the projecting tongues of the adjacent unit; said layeredges being formed to take a position in front of one another inopposite layers for counteracting communication between neighboringgaps.